Results 1 to 10 of about 50,452 (268)

X-Ray Evolution of Active Galactic Nuclei and Hierarchical Galaxy Formation [PDF]

, 2004
We have incorporated the description of the X-ray properties of Active Galactic Nuclei (AGNs) into a semi-analytic model of galaxy formation, adopting physically motivated scaling laws for accretion triggered by galaxy encounters.
A. Cavaliere, Fabrizio Fiore, G. C. Perola, G. C. Perola, Nicola Menci   +4 more
core   +5 more sources

A High Fraction of Heavily X-Ray-obscured Active Galactic Nuclei [PDF]

The Astrophysical Journal, 2023
We present new estimates on the fraction of heavily X-ray-obscured, Compton-thick (CT) active galactic nuclei (AGNs) out to a redshift of z ≤ 0.8. From a sample of 540 AGNs selected by mid-infrared (MIR) properties in observed X-ray survey fields, we ...
Christopher M. Carroll, Tonima T. Ananna, Ryan C. Hickox, Alberto Masini, Roberto J. Assef, Daniel Stern, Chien-Ting J. Chen, Lauranne Lanz   +7 more
doaj   +2 more sources

The Lively Accretion Disk in NGC 2992. III. Tentative Evidence of Rapid Ultrafast Outflow Variability

The Astrophysical Journal, 2023
We report on the 2019 XMM-Newton+NuSTAR monitoring campaign of the Seyfert galaxy NGC 2992, observed at one of its highest flux levels in the X-rays.
Alfredo Luminari, Andrea Marinucci, Stefano Bianchi, Barbara de Marco, Chiara Feruglio, Giorgio Matt, Riccardo Middei, Emanuele Nardini, Enrico Piconcelli, Simonetta Puccetti, Francesco Tombesi   +10 more
doaj   +1 more source

Narrow Fe–Kα Reverberation Mapping Unveils the Deactivated Broad-line Region in a Changing-look Active Galactic Nucleus

The Astrophysical Journal, 2023
“Changing-look active galactic nuclei” (CLAGNs) are known to change their apparent types between types 1 and 2, usually accompanied by a drastic change in their luminosity on timescales of years.
Hirofumi Noda, Taisei Mineta, Takeo Minezaki, Hiroaki Sameshima, Mitsuru Kokubo, Taiki Kawamuro, Satoshi Yamada, Takashi Horiuchi, Hironori Matsumoto, Makoto Watanabe, Kumiko Morihana, Yoichi Itoh, Koji S. Kawabata, Yasushi Fukazawa   +13 more
doaj   +1 more source

Testing Physical Scenarios for the Reflection Features of Type-1 AGNs using XMM-Newton and NuSTAR Simultaneous Observations

The Astrophysical Journal, 2023
Above ∼3 keV, the X-ray spectrum of active galactic nuclei (AGNs) is characterized by the intrinsic continuum and Compton reflection features. For type-1 AGNs, several regions may contribute to the reflection.
César Ivan Victoria-Ceballos, Omaira González-Martín, Josefa Masegosa, Anna Lia Longinotti, Donaji Esparza-Arredondo, Natalia Osorio-Clavijo   +5 more
doaj   +1 more source

AMUSE-Antlia. I. Nuclear X-Ray Properties of Early-type Galaxies in a Dynamically Young Galaxy Cluster

The Astrophysical Journal, 2023
To understand the formation and growth of supermassive black holes (SMBHs) and their coevolution with host galaxies, it is essential to know the impact of environment on the activity of active galactic nuclei (AGNs).
Zhensong Hu, Yuanyuan Su, Zhiyuan Li, Kelley M. Hess, Ralph P. Kraft, William R. Forman, Paul E. J. Nulsen, Sarrvesh S. Sridhar, Andra Stroe, Junhyun Baek, Aeree Chung, Dirk Grupe, Hao Chen, Jimmy A. Irwin, Christine Jones, Scott W. Randall, Elke Roediger   +16 more
doaj   +1 more source

Sources of X-rays from galaxies [PDF]

, 2011
Galactic X-ray emission is a manifestation of various high-energy phenomena and processes. The brightest X-ray sources are typically accretion-powered objects: active galactic nuclei and low- or high-mass X-ray binaries.
Liu, Persic, Porquet, Q. Daniel Wang, Revnivtsev, Revnivtsev, Sazonov, Tüllmann, Weźgowiec, Yuan, Zhang   +10 more
core   +1 more source

A Reemerging Bright Soft X-Ray State of the Changing-look Active Galactic Nucleus 1ES 1927+654: A Multiwavelength View

The Astrophysical Journal, 2023
1ES1927+654 is a nearby active galactic nucleus (AGN) that has shown an enigmatic outburst in optical/UV followed by X-rays, exhibiting strange variability patterns at timescales of months to years.
Ritesh Ghosh, Sibasish Laha, Eileen Meyer, Agniva Roychowdhury, Xiaolong Yang, J. A. Acosta–Pulido, Suvendu Rakshit, Shivangi Pandey, Josefa Becerra González, Ehud Behar, Luigi C. Gallo, Francesca Panessa, Stefano Bianchi, Fabio La Franca, Nicolas Scepi, Mitchell C. Begelman, Anna Lia Longinotti, Elisabeta Lusso, Samantha Oates, Matt Nicholl, S. Bradley Cenko, Brendan O’Connor, Erica Hammerstein, Jincen Jose, Krisztina Éva Gabányi, Federica Ricci, Sabyasachi Chattopadhyay   +26 more
doaj   +1 more source

X-ray power law spectra in active galactic nuclei [PDF]

, 2010
X-ray spectra of active galactic nuclei (AGN) are usually described as power law spectra, characterized by the spectral slope $\alpha$ or photon index $\Gamma$. Here we discuss the X-ray spectral properties within the framework of clumpy accretion flows,
Courvoisier, Deluit, Ishibashi, Ishibashi, Kelly, Laor, McHardy, McLure, Middleton, Nandra, Niko▯ajuk, Page, Papadakis, Papadakis, Piconcelli, Porquet, Reeves, Risaliti, Shemmer, Shemmer, Soldi, T. J.-L. Courvoisier, Titarchuk, Titarchuk, W. Ishibashi, Zdziarski, Zdziarski, Zdziarski   +27 more
core   +1 more source

X-ray bolometric corrections for Compton-thick active galactic nuclei [PDF]

, 2017
We present X-ray bolometric correction factors, $\kappa_{Bol}$ ($\equiv L_{Bol}/L_X$), for Compton-thick (CT) active galactic nuclei (AGN) with the aim of testing AGN torus models, probing orientation effects, and estimating the bolometric output of the ...
Ballantyne, D. R., Baloković, M., Bauer, F. E., Boorman, P., Brandt, W. N., Brightman, M., Buchner, J., Comastri, A., Del Moro, A., Farrah, D., Gandhi, P., Harrison, F. A., Koss, M., Lanz, L., Masini, A., Ricci, C., Stern, D., Vasudevan, R., Walton, D. J.   +18 more
core   +4 more sources